In current lighting applications, energy efficiency is a more and more important subject. One possible way to reduce the energy consumption of a lighting system is to switch off or dim one or more light sources thereof when no object (i.e. person or vehicle) is present in a space, and conversely to switch on the light(s) when an object moves into the space. In order to do this, the presence of an object in the relevant space has to be detected. Different types of motion sensors are currently in use.
There is a strong need for sensor-driven light control systems, because of their advantage of bringing down the energy consumption of the light source(s) thereof, and thereby improving cost-savings, and life-time of the light source(s).
Outdoor lighting installations may for example detect the motion of pedestrians at street crossings, or traffic density (vehicle count over time) for deployments on highways. Known solutions are based on either installing external optical sensors (cameras, PIRs, etc.) to a lighting pole or directly integrating similar sensor modules to a lighting board. Narrow field of view (FOV) sensors are inexpensive to provide, but for object detection disadvantageously have a strong requirement that the sensor is orientated at a specific position to aim the narrow FOV such that objects will be detected, and the observation area is very limited. Therefore known solutions require the sensors to have wide FOVs to achieve the required responsiveness, which is expensive to provide.